/*

 * Copyright (c) 2009, 2018, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package org.graalvm.compiler.lir;

import static org.graalvm.compiler.lir.LIRValueUtil.isVirtualStackSlot;

import static jdk.vm.ci.code.ValueUtil.asAllocatableValue;

import static jdk.vm.ci.code.ValueUtil.isConstantJavaValue;

import static jdk.vm.ci.code.ValueUtil.isIllegalJavaValue;

import static jdk.vm.ci.code.ValueUtil.isVirtualObject;

import java.util.Arrays;

import java.util.EnumSet;

import org.graalvm.compiler.lir.LIRInstruction.OperandFlag;

import org.graalvm.compiler.lir.LIRInstruction.OperandMode;

import org.graalvm.compiler.lir.framemap.FrameMap;

import org.graalvm.compiler.lir.util.IndexedValueMap;

import jdk.vm.ci.code.BytecodeFrame;

import jdk.vm.ci.code.DebugInfo;

import jdk.vm.ci.code.StackLockValue;

import jdk.vm.ci.code.VirtualObject;

import jdk.vm.ci.meta.AllocatableValue;

import jdk.vm.ci.meta.JavaValue;

import jdk.vm.ci.meta.Value;

/**

 * This class represents garbage collection and deoptimization information attached to a LIR

 * instruction.

 */

public class LIRFrameState {

    public static final LIRFrameState NO_STATE = new LIRFrameState(null, null, null);

    public final BytecodeFrame topFrame;

    private final VirtualObject[] virtualObjects;

    public final LabelRef exceptionEdge;

    protected DebugInfo debugInfo;

    private IndexedValueMap liveBasePointers;

    public LIRFrameState(BytecodeFrame topFrame, VirtualObject[] virtualObjects, LabelRef exceptionEdge) {

        this.topFrame = topFrame;

        this.virtualObjects = virtualObjects;

        this.exceptionEdge = exceptionEdge;

    }

    public boolean hasDebugInfo() {

        return debugInfo != null;

    }

    public DebugInfo debugInfo() {

        assert debugInfo != null : "debug info not allocated yet";

        return debugInfo;

    }

    /**

     * Iterates the frame state and calls the {@link InstructionValueProcedure} for every variable.

     *

     * @param proc The procedure called for variables.

     */

    public void forEachState(LIRInstruction inst, InstructionValueProcedure proc) {

        for (BytecodeFrame cur = topFrame; cur != null; cur = cur.caller()) {

            processValues(inst, cur.values, proc);

        }

        if (virtualObjects != null) {

            for (VirtualObject obj : virtualObjects) {

                processValues(inst, obj.getValues(), proc);

            }

        }

        if (liveBasePointers != null) {

            liveBasePointers.forEach(inst, OperandMode.ALIVE, STATE_FLAGS, proc);

        }

    }

    /**

     * Iterates the frame state and calls the {@link InstructionValueConsumer} for every variable.

     *

     * @param proc The procedure called for variables.

     */

    public void visitEachState(LIRInstruction inst, InstructionValueConsumer proc) {

        for (BytecodeFrame cur = topFrame; cur != null; cur = cur.caller()) {

            visitValues(inst, cur.values, proc);

        }

        if (virtualObjects != null) {

            for (VirtualObject obj : virtualObjects) {

                visitValues(inst, obj.getValues(), proc);

            }

        }

        if (liveBasePointers != null) {

            liveBasePointers.visitEach(inst, OperandMode.ALIVE, STATE_FLAGS, proc);

        }

    }

    /**

     * We filter out constant and illegal values ourself before calling the procedure, so

     * {@link OperandFlag#CONST} and {@link OperandFlag#ILLEGAL} need not be set.

     */

    protected static final EnumSet<OperandFlag> STATE_FLAGS = EnumSet.of(OperandFlag.REG, OperandFlag.STACK);

    protected void processValues(LIRInstruction inst, JavaValue[] values, InstructionValueProcedure proc) {

        for (int i = 0; i < values.length; i++) {

            JavaValue value = values[i];

            if (isIllegalJavaValue(value)) {

                continue;

            }

            if (value instanceof AllocatableValue) {

                AllocatableValue allocatable = (AllocatableValue) value;

                Value result = proc.doValue(inst, allocatable, OperandMode.ALIVE, STATE_FLAGS);

                if (!allocatable.identityEquals(result)) {

                    values[i] = (JavaValue) result;

                }

            } else if (value instanceof StackLockValue) {

                StackLockValue monitor = (StackLockValue) value;

                JavaValue owner = monitor.getOwner();

                if (owner instanceof AllocatableValue) {

                    monitor.setOwner((JavaValue) proc.doValue(inst, (AllocatableValue) owner, OperandMode.ALIVE, STATE_FLAGS));

                }

                Value slot = monitor.getSlot();

                if (isVirtualStackSlot(slot)) {

                    monitor.setSlot(asAllocatableValue(proc.doValue(inst, slot, OperandMode.ALIVE, STATE_FLAGS)));

                }

            } else {

                assert unprocessed(value);

            }

        }

    }

    protected void visitValues(LIRInstruction inst, JavaValue[] values, InstructionValueConsumer proc) {

        for (int i = 0; i < values.length; i++) {

            JavaValue value = values[i];

            if (isIllegalJavaValue(value)) {

                continue;

            } else if (value instanceof AllocatableValue) {

                proc.visitValue(inst, (AllocatableValue) value, OperandMode.ALIVE, STATE_FLAGS);

            } else if (value instanceof StackLockValue) {

                StackLockValue monitor = (StackLockValue) value;

                JavaValue owner = monitor.getOwner();

                if (owner instanceof AllocatableValue) {

                    proc.visitValue(inst, (AllocatableValue) owner, OperandMode.ALIVE, STATE_FLAGS);

                }

                Value slot = monitor.getSlot();

                if (isVirtualStackSlot(slot)) {

                    proc.visitValue(inst, slot, OperandMode.ALIVE, STATE_FLAGS);

                }

            } else {

                assert unprocessed(value);

            }

        }

    }

    private boolean unprocessed(JavaValue value) {

        if (isIllegalJavaValue(value)) {

            // Ignore dead local variables.

            return true;

        } else if (isConstantJavaValue(value)) {

            // Ignore constants, the register allocator does not need to see them.

            return true;

        } else if (isVirtualObject(value)) {

            assert Arrays.asList(virtualObjects).contains(value);

            return true;

        } else {

            return false;

        }

    }

    /**

     * Called by the register allocator to initialize the frame state.

     *

     * @param frameMap The frame map.

     * @param canHaveRegisters True if there can be any register map entries.

     */

    public void initDebugInfo(FrameMap frameMap, boolean canHaveRegisters) {

        debugInfo = new DebugInfo(topFrame, virtualObjects);

    }

    public IndexedValueMap getLiveBasePointers() {

        return liveBasePointers;

    }

    public void setLiveBasePointers(IndexedValueMap liveBasePointers) {

        this.liveBasePointers = liveBasePointers;

    }

    @Override

    public String toString() {

        return debugInfo != null ? debugInfo.toString() : topFrame != null ? topFrame.toString() : "<empty>";

    }

}